A number of applications may require that approaching human or vehicles threats, and any suspicious activity around a protected area, be detected. For example, suicide bombers or vehicles loaded with explosive material may have to be detected nearing a secured zone.
Human footsteps and approaching vehicles generate seismic waves which can be captured by seismic sensors. Seismic energy varies as a function of the weight of the vehicle or human, style of driving or walking, and type of substrate. An object moving near a secured zone acts as a source of seismic vibration which generates different type of surface waves (Rayleigh, P, and S, for example). These waves propagate at different speed and dissipate in different relative distances depending on the frequency characteristics of the seismic waves and the type of substrate.
In general, low frequency bands of the seismic waves have higher energy than higher frequency bands. Therefore, for the purpose of classification of vibration sources, relying on only low frequency features of the seismic wave results in a poor classification rate.
There is a need for systems and methods for detecting and reporting security breach events, that are more reliable and that provide better functionalities.